After learning John has taken the time machine to 1918 in Paris, H.G. is determined to stop him before he can alter the fabric of time.
Dr. John Stevenson has met his match in a stunning - and equally cunning - doctor named Brooke, while H.G. and Jane travel back to the 1980's where they make a shocking discovery that could change Vanessa's life.
H.G. and Jane rush to repair the damaged time machine before Dr. John Stevenson - now better known as "The Key Killer" - strikes again. Meanwhile, Vanessa must decide whether or not to confide in Griffin.